diff --git a/desmume/src/frontend/windows/CWindow.h b/desmume/src/frontend/windows/CWindow.h
index a734d7076..5be01854c 100644
--- a/desmume/src/frontend/windows/CWindow.h
+++ b/desmume/src/frontend/windows/CWindow.h
@@ -285,7 +285,7 @@ public:
 
 protected:
 	DWORD		threadID;
-	virtual DWORD ThreadFunc()=NULL;
+	virtual DWORD ThreadFunc()=0;
 };
 
 class TOOLSCLASS : public THREADCLASS